In 1965, Gibson worked as the news director for Princeton University's student-run radio station, a radio producer for RKO, and a reporter for local television stations. In 1975, he joined ABC News, where he worked as a general assignment reporter and a correspondent from Washington, D.C..

On February 23, 1987, Gibson first became a co-anchor of Good Morning America, alongside Joan Lunden. From 1985 to 1995, Good Morning America was the most-watched morning show on American television.[3]

During the 1992 presidential campaign, Vice President Dan Quayle used part of an interview between Gibson and Reform Party candidate Ross Perot to claim that Perot displayed contempt towards the United States Constitution. On the October 22, 1991, edition of Good Morning America, Gibson asked Perot what Perot would advise President George H. W. Bush to do to "jump-start the economy". Perot stated that the U.S. helped Germany and Japan write their respective nations' constitutions: "This was at a time when the industrial revolution had occurred. Our Constitution was written 200 years ago, before it occurred." He added that those nations "have an intelligent relationship between business and government." Vice President Quayle responded: "Mr. Perot, we do not need a new constitution. Our Constitution has served us well."[5] When Gibson interviewed Democratic presidential candidate and then-Governor of ArkansasBill Clinton on June 28, 1992, The New York Times noted that Gibson repeatedly pressed Clinton to name his vice presidential candidate.[6] Gibson interviewed President Bush on October 9 that year; Bush stated that he questioned Clinton's judgment, not patriotism, in traveling to the Soviet Union in 1969.[7]

On May 1, 1998, Gibson left the program and ABC replaced him with Kevin Newman.[8] Newman began hosting Good Morning America on May 4, 1998.[9]Good Morning America then began losing viewers to NBC's Today show. In May 1996, Good Morning averaged 4.17 million viewers daily, and Today averaged 4.43 million; that gap expanded to 3.12 for Good Morning and 5.26 for Today.[3] ABC reinstated Gibson to Good Morning America on January 18, 1999 with Diane Sawyer as co-host.[10] He remained as co-anchor until June 28, 2006 when he left to anchor World News Tonight, after having spent 19 years with the morning program. In 1998 and 1999, he was a co-anchor, with Connie Chung, on the Monday edition of the ABC newsmagazine program 20/20.

In the summer of 2005, Gibson began substitute anchoring World News Tonight (its name at the time) regularly after long-time anchor Peter Jennings's treatment for lung cancer prevented him from anchoring. On August 7, 2005, Gibson announced Jennings's death and the following day anchored World News Tonight, and was eventually offered the job.

Though Gibson was a leading choice to replace Jennings, he could not agree with David Westin, President of ABC News, over how long he would be anchor.[12] On January 2, 2006, Elizabeth Vargas and Bob Woodruff, veteran ABC News journalists, were chosen to be Jennings's permanent replacements. They had both been interim anchors. Vargas had been designated by Peter Jennings as only favored choice as back up anchor on September 11, 2001.

Following Woodruff's severe injury on January 29, 2006, while on assignment in Iraq, and Vargas's announcement that she was pregnant, some critics questioned whether Vargas could sustain the program on her own, pointing to falling ratings. In July 2006, Cindy Adams of the New York Post reported that Gibson would become Woodruff's "Temporary Permanent Replacement" on World News Tonight.[13] According to some reports, while GMA co-host Diane Sawyer had coveted the World News Tonight anchor chair, Gibson had one year on his contract left and threatened to retire if he didn't get that position, and as GMA was ABC News' most lucrative show, it would be badly damaged if it lost both Sawyer and Gibson.[14]

On May 29, 2006, Gibson was named sole anchor of World News Tonight, effective May 23, 2006, after Vargas announced her resignation from the program. She cited her doctors' recommendation to reduce considerably her workload because of her upcoming maternity leave, and her wish to spend more time with her new baby.[15] She would return to anchor 20/20.

During the summer of 2006, the program's title was changed to World News with Charles Gibson. According to The New York Times, he had previously planned to retire from ABC News on June 22, 2007, but remained to anchor the newscast.[16]

On September 11, 2008, Gibson interviewed Sarah Palin, the 2008 Republican vice-presidential nominee candidate, her first interview after being named as presidential nominee John McCain's running mate. The interview received criticism from political commentators such as Charles Krauthammer, specifically surrounding Gibson's question regarding the term 'Bush Doctrine' due to its having a variety of differing meanings.[20][21]

During Gibson's tenure, World News was a solid competitor and sporadically beat NBC Nightly News, anchored by Brian Williams, in the program ratings during 2007, the first time in several years, and the ABC program became much more distant second place after he retired.[22] The two programs have taken turns at the top of the ratings among household viewers and the 25–54 age group prized by advertisers. Katie Couric's CBS Evening News remained a distant third.[23][24] During his last few months as anchor, Gibson also worked on a special documentary about the oil industry entitled "Over a Barrel: The Truth About Oil," which was a critical and ratings success and earned him several awards.

According to reports, while ABC tried to persuade Gibson to stay on as anchor, he decided to retire.[25] On September 2, 2009, ABC News announced that Diane Sawyer would replace Gibson at the "World News" anchor chair following his retirement from ABC News. Gibson anchored his final edition of World News on December 18, 2009.[26]

On June 17, 2007, Gibson delivered the commencement address to the class of 2007's graduation ceremony at Union College in Schenectady, New York.[42] Gibson also received an honorary doctor of humane letters, as well as a framed copy of his father's 1923 college yearbook entry. His father, Burdett Gibson, grew up in Schenectady and graduated from the college in 1923.[43] Gibson contributed an estimated US$75,000 to the college to help create the Burdett Gibson Class of 1923 Scholarship, which is awarded annually to a deserving student in need.[44]

^Lawler, Sylvia. "CHARLES GIBSON PERFECTLY HAPPY AS 'GMA' EQUAL", The Morning Call, August 30, 1987. Accessed February 17, 2011. ""Charlie, his wife Arlene, and their two daughters, had just spent their first night in a new home in Summit, N.J., where Mrs. Gibson is headmistress of a girls school before he headed out west to talk to the press."